iOS实现图片自动切换效果

本文实例为大家分享了ios实现图片自动切换的具体代码，供大家参考，具体内容如下

#import "viewcontroller.h"
#define imageviewcount 5
 
@interface viewcontroller ()<uiscrollviewdelegate>
 
@property (weak, nonatomic) iboutlet uiscrollview *imagescrollview;
@property (weak, nonatomic) iboutlet uipagecontrol *imageviewpagecontrol;
@property (strong, nonatomic) nstimer *timer;
@end
 
@implementation viewcontroller
 
- (void)viewdidload {
 [super viewdidload];
 
 [self addimageview2scrollview];
 self.imagescrollview.contentsize = cgsizemake(self.imagescrollview.frame.size.width * imageviewcount, 0);
 
 self.imagescrollview.delegate = self;
 self.imagescrollview.pagingenabled = yes;//uiscrollview支持拖动分页
 self.imageviewpagecontrol.numberofpages = imageviewcount;
 
 [self addscrolltimer];
}
 
- (void)rotatepic{
 int currentpageindex = self.imageviewpagecontrol.currentpage;
 if(++currentpageindex == 5){
  currentpageindex = 0;
 }
 cgfloat offsetx = currentpageindex * self.imagescrollview.frame.size.width;
 [uiview animatewithduration:1 animations:^{
  self.imagescrollview.contentoffset = cgpointmake(offsetx, 0);
 }];
}
 
/**添加图片到imagescrollview*/
- (void)addimageview2scrollview{
 cgfloat imagewidth = self.imagescrollview.frame.size.width;
 cgfloat imageheight = self.imagescrollview.frame.size.height;
 for(int i = 0;i <= imageviewcount;i++){
  uiimageview *imageinscroll = [[uiimageview alloc] init];
  imageinscroll.frame = cgrectmake(i * imagewidth, 0, imagewidth, imageheight);
  imageinscroll.image = [uiimage imagenamed:[nsstring stringwithformat:@"img_%02d",i + 1]];
  [self.imagescrollview addsubview:imageinscroll];
 }
}
 
// 正滚动时执行
- (void)scrollviewdidscroll:(uiscrollview *)scrollview{
 cgfloat offx = self.imagescrollview.contentoffset.x;//（0，0）距离content内部左上顶点的x轴长度
 nslog(@"~~~~~~~%f ^^^^^^%f", offx, self.imagescrollview.frame.size.width);
 int currentpageindex = (offx + .5f * self.imagescrollview.frame.size.width) / self.imagescrollview.frame.size.width;
 self.imageviewpagecontrol.currentpage = currentpageindex;
}
 
- (void)addscrolltimer{
 self.timer = [nstimer timerwithtimeinterval:2 target:self selector:@selector(rotatepic) userinfo:nil repeats:yes];
 [[nsrunloop mainrunloop] addtimer:self.timer formode:nsrunloopcommonmodes];
}
 
- (void)removescrolltimer{
 [self.timer invalidate];//释放定时器
 self.timer = nil;
}
 
// 开始准备滚动时执行 移除定时滚动操作
- (void)scrollviewwillbegindragging:(uiscrollview *)scrollview{
 nslog(@"~~~scrollviewwillbegindragging");
 [self removescrolltimer];
}
 
// 结束滚动后执行 添加定时滚动操作
- (void)scrollviewdidenddragging:(uiscrollview *)scrollview willdecelerate:(bool)decelerate{
 nslog(@"~~~scrollviewdidenddragging");
 [self addscrolltimer];
}
@end

对uiscrollview的运用，以上代码中有详细注释，需注意2点：

1.注意设置contentsize属性。其中contentsize表示scroll内容尺寸大小

2.注意设置代理uiscrollviewdelegate，才可调用其中的方法

对于定时器nstimer的运用需注意

1.在线程的loop中添加定时器

2.注意使用完成回收nstimer

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。